better thread handling and removal of unused code.

src/main/java/carpet/script/value/Value.java

@@ -24,21 +24,6 @@ public abstract class Value implements Comparable<Value>, Cloneable
 
     public String boundVariable;
 
-    public static <T> T assertNotNull(T t)
-    {
-        if (t == null)
-            throw new InternalExpressionException("Operand may not be null");
-        return t;
-    }
-
-    public static <T> void assertNotNull(T t1, T t2)
-    {
-        if (t1 == null)
-            throw new InternalExpressionException("First operand may not be null");
-        if (t2 == null)
-            throw new InternalExpressionException("Second operand may not be null");
-    }
-
     public boolean isBound()
     {
         return boundVariable != null;